Abstract; Objective: To evaluate the relationship between changes in
physical fitness and risk of mortality in men.

Design: Prospective study, with two clinical examinations (mean interval
between examinations, 4.9 years) to assess change or lack of change in
physical fitness as associated with risk of mortality during follow-up after
the subsequent examination (mean follow-up from subsequent examination, 5.1
years).

Setting: Preventive medicine clinic.

Study Participants: Participants were 9777 men given two preventive medical
examinations, each of which included assessment of physical fitness by
maximal exercise tests and evaluation of health status.

Results: The highest age-adjusted all-cause death rate was observed in men
who were unfit at both examinations (122.0/10,000 man-years); the lowest
death rate was in men who were physically fit at both examinations
(39.6/10,000 man-years). Men who improved from unfit to fit between the
first and subsequent examinations had an age-adjusted death rate of
67.7/10,000 man-years. This is a reduction in mortality risk of 44% (95%
confidence interval, 25% to 59%) relative to men who remained unfit at both
examinations. Improvement in fitness was associated with lower death rates
after adjusting for age, health status, and other risk factors of premature
mortality. For each minute increase in maximal treadmill time between
examinations, there was a corresponding 7.9% (P = .001) decrease in risk of
mortality. Similar results were seen when the group was stratified by health
status, and for cardiovascular disease mortality.

Conclusions: Men who maintained or improved adequate physical fitness were
less likely to die from all causes and from cardiovascular disease during
follow-up than persistently unfit men. Physicians should encourage unfit men
to improve their fitness by starting a physical activity program.